C. C and Pb; Carbon and Lead being in the same group.
I'm pretty sure that significant figures is just the amount of numbers there is. So, in this case I think the answer would be D. 5
Well a compound is 2 or more different molecules together. So if you see a periodic table you will see the elements to see if they are the same or not.
A drop of iquid mercury is D. <span> a pure substance and an element. This is because mercury is an element which exists as liquid in the normal or standard conditions. It is a metal that is toxic to all environments. It is pure because it is composed only of one kind of substance.</span>
